1. Field of the Invention
The invention relates generally to portable data carriers, such as smart cards or compact memory modules of various types. More specifically, the invention relates to the loading of media data, such as image data or audio data or video data, into such data carriers.
2. Description of the Related Art
Portable data carriers for the storage of media data are well known in various forms. The article entitled “Das Gigabyte im Geldbeutel” by Clemens Gleich in c't magazine, Heise-Verlag, Issue Aug. 2002, pages 164 to 166, gives an overview of the products currently offered under the trademarks and trade names CompactFlash, SmartMedia, Memory Stick, Secure Digital and MultiMediaCard. A version of the Memory Stick called Magic Gate and also the Secure Digital cards have digital rights management systems to prevent unauthorized copying of the media data. Such systems are described in the article “Blitzgescheit” by Clemens Gleich in c't magazine, Heise-Verlag, Issue August 2002, pages 168 to 172, especially in the box on page 169.
The problem of copy protection for media data that is secure but at the same time does not interfere with legitimate use has still not been satisfactorily solved, however. Security vulnerabilities exist, for example, when the user downloads media data onto the data carrier from a server of the rights holder. The user will usually use for this an Internet browser to access the server and store the media data intermediately on a personal computer belonging to the user. It is only in a second step that the media data are then exported to the data carrier. The media data stored in the user's personal computer are unprotected, however, and can easily be duplicated.
Other general problems of the prior art are concerned with the difficulty of reliable authentication of the eventual recipient of the media data with the server and the difficulty of secure key management.